title: Phenotypic variation in nurse traits and community feedbacks define an alpine community.
abstract: Much is known about facilitation, but virtually nothing about the underlying genetic and evolutionary consequences of this important interaction. We assessed the potential of phenotypic differences in facilitative effects of a foundation species to determine the composition of an Alpine community in Arizona. Two phenotypes of Geum rossii occur along a gradient of disturbance, with 'tight' competitive cushions in stable conditions and 'loose' facilitative cushions in disturbed conditions. A common-garden study suggested that field-based traits may have a genetic basis. Field experiments showed that the reproductive fitness of G. rossii cushions decreased with increasing facilitation. Finally, using a dual-lattice model we showed that including the cost and benefit of facilitation may contribute to the co-occurrence of genotypes with contrasting facilitative effects. Our results indicate that changes in community composition due to phenotypic differences in facilitative effects of a foundation species may in turn affect selective pressures on the foundation species.
authors.affiliation: University Bordeaux 1, UMR INRA 1202 BIOGECO, 33405 Talence, France. r.michalet@ecologie.u-bordeaux1.fr
authors.forename: Richard
authors.initials: R
authors.lastname: Michalet
authors.forename: Sa
authors.initials: S
authors.lastname: Xiao
authors.forename: Blaise
authors.initials: B
authors.lastname: Touzard
authors.forename: David S
authors.initials: DS
authors.lastname: Smith
authors.forename: Lohengrin A
authors.initials: LA
authors.lastname: Cavieres
authors.forename: Ragan M
authors.initials: RM
authors.lastname: Callaway
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Whitham
mesh_terms: D001130:Arizona; D017753:Ecosystem; D005838:Genotype; D031986:Geum / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology*; D008954:Models, Biological; D010641:Phenotype; D018515:Plant Leaves / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology; D018517:Plant Roots / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology; D018547:Plant Stems / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology; D011157:Population Dynamics; D012641:Selection, Genetic